need guidance to the right disconnect and Circuit breakers or fuses online, please...

pyana1

my charge controller manual reads:

"Circuit breakers or fuses must be installed in both the battery and solar circuits. The protection
device ratings and installation methods must conform to NEC requirements.
The battery circuit fuse or circuit breaker must be rated to 125% of the maximum current or more.
The minimum fuse/breaker rating allowed for use with each TriStar MPPT model is listed in table
3-3.


_________________________________________________________________________
Model: Minimum battery circuit fuse/breaker rating:
TS-MPPT-45 1.25 x 45 Amps = 56.3 Amps
_________________________________________________________________________
Table 3-3 Minimum battery circuit fuse/breaker ratings per NEC requirements

A disconnect is required for the battery and solar circuits to provide a means for removing power
from the TriStar MPPT. Double pole switches or breakers are convenient for disconnecting both
solar and battery conductors simultaneously."

BB.

Re: need guidance to the right disconnect and Circuit breakers or fuses online, please..

I am not sure that I would bother to go with a double pole breaker for Vpanel input and Vbatt output of the charge controller. Most work well with an on/off/breaker/switch on the Vpanel input, and a second breaker on the Vbatt output.

In general, most controllers like to have Vbatt connected first and disconnected last.

You only "need" a breaker/fuse on the solar panels when you have three or more parallel strings of solar panels. One breaker on each string. If there is a short in one string, that breaker will prevent too much current from the other 2+ strings feeding into that short.

If you use a combiner box+breakers on the solar panel side, you do not need a second breaker/disconnect switch on the Vpanel input--Your choice if you want a second series breaker/switch (if combiner box is 100' away on the array, a second switch/breaker near the charge controller may be a nice to have.

One of the important specs when choosing a breaker/fuse are their voltage and AC/DC ratings. You can find many breakers/fuses/switches rated for 12 or 24 VDC. Fewer are to be found that are rated in the 48 to 600 VDC range.

If you purchase a pre wired/configured Combiner Box (plus fuse/breakers) and an E-Panel--It can save you a bunch of time trying to get all the pieces together.

http://www.solar-electric.com/installation-parts-and-equipment/midnite.html

You can find E-Panels from Midnite for many different vendor installations. And the other vendors (Outback, Schneider, etc.) also make their own pre-wired panels too.

-Bill

Cariboocoot

Re: need guidance to the right disconnect and Circuit breakers or fuses online, please..

pyana1 wrote: »

Double pole switches or breakers are convenient for disconnecting both
solar and battery conductors simultaneously."

This is not really a good idea as you may not want to shut down batt & PV at the same time. In fact the normal operation method is:

Connect battery to controller first, then connect PV.
Disconnect PV from controller first, then battery.

I don't know why they'd suggest switching them simultaneously, and it probably wouldn't happen that way anyhow.

You do need a 60 Amp fuse or breaker on the controller output. Disconnect is optional, and if you use a breaker it is redundant. Local code may not agree.

As for the input side, a disconnect is not electrically necessary just convenient. Over-current protection on the array as a whole is unnecessary. Again local code may not agree.

As Bill said if you have more than two parallel PV connections each and every should have over-current protection sized according to the maximum series fuse rating of the panels. NEC derating does not apply to this, no matter what anyone says, as the MSFR is already above Isc.

Our host has all sorts of equipment like this available, just to give you an idea: http://www.solar-electric.com/installation-parts-and-equipment/midnite.html